Process for producing highly reactive low-viscosity modified phenolic resins

ABSTRACT

A process for producing a highly reactive low-viscosity modified phenolic resin comprising the steps of polycondensating a petroleum heavy oil or pitch, a formaldehyde polymer, and a phenol in the presence of an acid catalyst to prepare a modified phenolic resin; and reacting the resultant modified phenolic resin with the phenols at a temperature higher than 120° C. and not more than 200° C. in the presence of the acid catalyst to lower the molecular weight of the modified phenolic resin. The highly reactive low-viscosity modified phenolic resin obtained according to this process has high reactivity with epoxy resins and low resin melt viscosity. In addition, this resin can be used for producing a molding material having good moldability and considerably low moisture absorption when combined with an epoxy resin.

This application is a Divisional of application Ser. No. 08/797,631,filed on Feb. 7, 1997, now U.S. Pat. No. 5,792,826.

FIELD OF THE INVENTION

The present invention relates to a process for producing a highlyreactive, low-viscosity modified phenolic resin which is low in resinmelt viscosity and combinable with an epoxy resin to form a moldingmaterial which is excellent in moldability and has low moistureabsorption characteristics to provide an improved dimensional stabilitywith no change in dimension caused due to moisture absorption. Thepresent invention also relates to molding materials, materials forelectrical and electronic parts and semiconductor sealers, based on amodified phenolic resin comprising the highly reactive, low-viscositymodified phenolic resin obtained through this process and an epoxyresin.

BACKGROUND OF THE INVENTION

The phenolic resin provides a molding excellent in mechanicalproperties, and hence has widely been employed from of old eitherindependently or in the form of a blend with another resin, such as anepoxy resin. However, the phenolic resin per se and blend have drawbacksin that their light and alkali resistance is relatively low, that theyare likely to absorb water or an alcohol to thereby suffer from changesin the dimension and electrical resistance, and that the thermalresistance, especially the oxidation resistance at high temperatures,thereof is poor.

In order to overcome the drawbacks, various modifications of thephenolic resin have been studied. For example, various modified phenolicresins have been proposed, which have improved resistance todeterioration and oxidation due to light, chemicals, etc. by virtue ofthe modification using a fat, an oil, a rosin or a neutral aromaticcompound.

For example, Japanese Patent Laid-Open Publication No. 61(1986)-235413discloses a phenolic resin having excellent thermal resistance, obtainedby selecting reactants of a phenol-modified aromatic hydrocarbon resin.However, the phenolic resin obtained by this method is disadvantageouslynot cured unless being maintained at a high temperature for a prolongedperiod of time in the manufacturing of a molding by the use thereof.

Japanese Patent Laid-Open Publication No. 2(1990)-274714 discloses thata modified phenolic resin useful for a molding material, havingexcellent thermal and oxidation resistance and mechanical strength ascannot be expected from the conventional phenolic resin, is obtained byemploying a petroleum heavy oil or pitch, which is a cheap material, asa modifier material and by selecting specific reaction conditions.

Further, Japanese Patent Laid-Open Publication No. 4(1992)-145116discloses that, in the production of such a phenolic resin, a crudemodified phenolic resin obtained by a polycondensation of startingcompounds is subjected to a neutralization treatment, a water washingtreatment and/or an extraction treatment to thereby neutralize andremove any acid remaining in the crude modified phenolic resin, so thata modified phenolic resin which does not corrode a metal member broughtinto contact with the resin is provided.

In the above process for producing the modified phenolic resin, the acidremaining in the crude modified phenolic resin is actually neutralizedand removed by the neutralization treatment using an amine, followed bythe water washing treatment. However, the modified phenolic resinobtained through the purification step involving the aboveneutralization and water washing treatments is likely to retain aneutralization product therein, so that there is a problem that it isunsatisfactory as a molding material used for a product on which strictrequirements for thermal and corrosion resistance are imposed, such as amolding material for electrical or electronic part and a material forsemiconductor sealer.

Japanese Patent Laid-Open Publication No. 6(1994)-228157 teaches that amodified phenolic resin containing substantially no acid can be obtainedby purifying a crude modified phenolic resin through a purification stepincluding a specific extraction treatment. The modified phenolic resincontaining substantially no acid, obtained through this purificationstep, may be combined with an epoxy resin, so that a molding materialcan be obtained, which not only has excellent thermal and moistureresistance but also does not corrode any metals.

However, the above modified phenolic resin has a drawback in that themelt viscosity of the resin is so high that the resin is not suitablefor speedy mass production of a molded article having a complexconfiguration. In addition, further improvements of thermal resistance,dimensional stability and strength and other mechanical properties havebeen demanded in the use of the modified phenolic resin in combinationwith an epoxy resin.

The present inventors proposed a process for producing a highly reactivemodified phenolic resin having a low resin melt viscosity and animproved reactivity with the epoxy resins by means of reacting amodified phenolic resin with phenols in the presence of an acid catalystto thereby lower the molecular weight of the modified phenolic resin(Japanese Patent Laid-Open Publication No. 7(1995)-252339).

In the molecular weight lowering step of this process, it is consideredthat the acetal bonding and/or methylene ether bonding present in themolecule of the modified phenolic resin is broken and dissociated tothereby lower the molecular weight of the modified phenolic resin andthat phenols are bonded to dissociation terminals to increase a phenolcontent. Therefore, the molecular weight lowering reaction is typicallycarried out at a temperature at which the acetal bonding and/ormethylene ether bonding in the modified phenolic resin molecules arecleaved and dissociated, i.e., 50-120° C.

The highly reactive modified phenolic resins obtained as described aboveare relatively low in viscosity and are capable of providing a moldingmaterial having good thermal resistance and moldability, as well assuperior mechanical strength such as dimensional stability when combinedwith an epoxy resin.

However, the viscosity of the highly reactive modified phenolic resinobtained in the process described above is not sufficiently low thoughit is significantly lower than those of the conventional modifiedphenolic resins. Especially, in the application for semiconductorsealers, there has been a demand for a lower viscosity to furtherimprove the moldability while maintaining a high reactivity with theepoxy resin.

In this connection, resin molding materials tend to be expanded whenthey absorb moisture to deteriorate the dimensional stability. When theresin molding material is used for a composite material with a metalsuch as resin portions of electrical or electronic parts and, inparticular, for the semiconductor sealers, the moisture adsorbed by theresultant resin package rapidly vaporizes during solder mounting at ahigh temperature. This causes swelling and cracks of the resin package.The resin portions containing moisture may corrode a metal portion,significantly affecting lifetime and reliability of a resultant product.It has thus been desired to reduce moisture absorption of the moldingmaterial comprising the highly reactive modified phenolic resindescribed above, for the applications where the moisture absorption ofthe molding material is undesirable.

The inventors have made extensive and intensive studies with respect tosuch drawbacks associated with the prior art. As a result, it has beenfound that a modified phenolic resin having a lower viscosity thatcannot be obtained by a conventional molecular weight lowering reactionis produced while maintaining a high reactivity with epoxy resins bymeans of reacting a reaction product of polycondensation reaction as itis or after subjecting to purification with a phenol at a certaintemperature condition in the absence of a formaldehyde polymer and othercross-linking agents and in the presence of an acid catalyst to lowerthe molecular weight thereof, and that a molding material formed of acombination of this modified phenolic resin and an epoxy resin has alower moisture absorption. The present invention was thus completed.

OBJECT OF THE INVENTION

The present invention is made with a view toward overcoming the abovementioned problems in the prior art. An object of the present inventionis to provide a process for producing a highly reactive low-viscositymodified phenolic resin which has a high reactivity with epoxy resinsand a particularly low resin melt viscosity, and which can provide amolding material having good moldability and a low moisture absorptionwhen being combined with an epoxy resin.

Another object of the present invention is to provide a process forproducing a highly reactive modified phenolic resin, which is suitablefor producing a modified phenolic resin containing substantially noacid, so that it does not exhibit no corrosive action, in addition tohaving the above low resin melt viscosity and marked improvement in thereactivity with epoxy resins.

It is yet another object of the present invention to provide a moldingmaterial, in particular, including materials for electrical andelectronic parts and semiconductor sealers which comprises the highlyreactive low-viscosity modified phenolic resin having the resin meltviscosity at 150° C. of from 0.2 to 4.5 poises capable of accomplishingby the process of the present invention and an epoxy resin, and which isexcellent in moldability and capable of giving molded articles havinglow moisture absorption.

SUMMARY OF THE INVENTION

A process for producing a highly reactive low-viscosity modifiedphenolic resin according to the present invention comprising the stepsof polycondensating a petroleum heavy oil or pitch, a formaldehydepolymer, and a phenol in the presence of an acid catalyst to prepare amodified phenolic resin; and reacting the resultant modified phenolicresin with phenols at a temperature higher than 120° C. and not morethan 200° C., and preferably from 140° C. to 180° C. in the presence ofan acid catalyst but substantially in the absence of an formaldehydepolymer as a cross-linking agent to thereby lower the molecular weightof the modified phenolic resin.

Examples of the phenol advantageously used in the process of the presentinvention include hydroxybenzene compounds and hydroxynaphthalenecompounds. In particular, the resultant highly reactive low-viscositymodified phenolic resin has a particularly low resin melt viscosity whena hydroxybenzene compound is used as the phenol in the molecular weightlowering step. On the other hand, the thermal resistance and theresistance to moisture absorption of the resultant highly reactivelow-viscosity modified phenolic resin is especially improved when thehydroxynaphthalene compound is used as the phenol in the molecularweight lowering step.

In the process for producing a highly reactive low-viscosity modifiedphenolic resin according to the present invention, it is preferred that,in the polycondensation step, a mixture containing the petroleum heavyoil or pitch and the formaldehyde polymer in a ratio of the number ofmoles, in terms of formaldehyde, of the formaldehyde polymer to that ofthe petroleum heavy oil or pitch of 1:1 to 15:1 be heated underagitation in the presence of an acid catalyst, and that the phenol begradually added to the mixture while being heated under agitation untila ratio of the number of moles of the phenol to that of the petroleumheavy oil or pitch of 0.3:1 to 5:1 to thereby effect thepolycondensation of these starting materials.

In the present invention, the modified phenolic resin prepared in thepolycondensation step may be treated with (i) a solvent containing atleast one compound selected from the group consisting of aliphatic andalicyclic hydrocarbons each having up to 10 carbon atoms and/or (ii) anextraction solvent capable of dissolving the acid catalyst used in thepolycondensation in a solubility of 0.1 or less and a major portion ofthe modified phenolic resin, in order to extract and removesolvent-soluble components containing unreacted components and/orcatalyst residues, as well as the formaldehyde polymer as thecross-linking agent, so that the resultant modified phenolic resin ispurified prior to subjecting it to the molecular weight lowering step.Thus, it is effectively avoided to take with the acid catalyst residuesand the formaldehyde polymer used in the polycondensation step into themolecular weight lowering step.

A molding material based on the modified phenolic resin according to thepresent invention comprises (A) the highly reactive low-viscositymodified phenolic resin having the resin melt viscosity at 150° C. offrom 0.2 to 4.5 poises, particularly from 0.2 to 3.0 poises or from 1.0to 4.5 poises, obtainable according to the process as described aboveand (B) an epoxy resin. The modified phenolic resin may also comprise(C) a curing agent and/or a curing accelerator, and (D) an inorganicfiller in addition to the resin components (A) and (B).

It is preferable that the molding material based on the modifiedphenolic resin according to the present invention contain the highlyreactive low-viscosity modified phenolic resin (A) and the epoxy resin(B) in a weight ratio of 10:90 to 90:10.

The material for the electrical and electronic parts according to thepresent invention is characterized in that it is produced by molding theabove mentioned molding material based on the highly reactivelow-viscosity modified phenolic resin.

The semiconductor sealer according to the present invention comprisesthe above molding material based on the highly reactive low-viscositymodified phenolic resin.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described more in detail below.

In the process for producing the highly reactive low-viscosity modifiedphenolic resin according to the present invention, a modified phenolicresin obtained in a specific polycondensation step is lowered in itsmolecular weight in a molecular weight lowering step carried out under aspecific condition particularly at a higher temperature than that inconventional processes to thereby produce the highly reactivelow-viscosity modified phenolic resin.

In the polycondensation step of the process in the present invention,specifically, a petroleum heavy oil or pitch, a formaldehyde polymer,and phenols are polycondensed in the presence of an acid catalyst.

The petroleum heavy oil or the pitch used as a raw material in the abovementioned polycondensation reaction includes a distillation residue ofcrude oil, a hydrocracking residue, a catalytic cracking residue, athermal cracking residue of naphtha or LPG, and a vacuum distillate, anextract by solvent extraction and thermal treatment products from suchresidues. It is preferred that a petroleum heavy oil or pitch havingappropriate fraction of aromatic hydrocarbon (fa) and ratio of hydrogenof aromatic ring (Ha) be selected for use.

For example, it is preferred that the petroleum heavy oil or the pitchhave a value of fa ranging from 0.40 to 0.95, particularly from 0.5 to0.8, and a value of Ha ranging from 20 to 80%, particularly from 25 to60%.

The fraction of aromatic hydrocarbon (fa) and the ratio of hydrogen ofaromatic ring (Ha) are given by the following formulae from dataobtained by ¹³ C-NMR and ¹ H-NMR measurements on the petroleum heavy oilor the pitch, respectively. ##EQU1##

When the fa value of the petroleum heavy oil or pitch as a raw materialis smaller than 0.4, the aromatic content is low, so that it is likelythat the effect thereof on the improvement of the performance, such asthermal and oxidation resistance, of the resultant modified phenolicresin is less.

On the other hand, when the petroleum heavy oil or pitch has an fa valueof greater than 0.95, the reactivity of hydrogen atoms of aromatic ringswith formaldehyde is likely to become unfavorably low.

When the Ha value of the petroleum heavy oil or pitch as a raw materialis smaller than 20%, the amount of aromatic ring hydrogen atoms reactingwith formaldehyde is less to thereby cause the reactivity lowering, sothat the effect thereof on the improvement of the performance of thephenolic resin is likely to become poor.

On the other hand, when a petroleum heavy oil or pitch having an Havalue of greater than 80% is used as a raw material, the strength of themodified phenolic resin is likely to become poor.

With respect to the aromatic hydrocarbon composing the petroleum heavyoil or pitch used in the present invention, the number of condensedrings is not particularly limited. However, it is generally preferredthat the petroleum heavy oil or pitch be mainly composed of polycyclicaromatic hydrocarbons each having 2 to 4 condensed rings. When thepetroleum heavy oil or pitch contains condensed polycyclic aromatichydrocarbons each having at least 5 condensed rings at a high content,such condensed polycyclic aromatic hydrocarbons have generally highboiling points, e.g., over 450° C., so that boiling point variancesbecome large and the aromatic hidrocarbons composing the petroleum heavyoil or pitch cannot be in the narrow range of the boiling point tothereby cause the quality of the product to be unstable. On the otherhand, when the petroleum heavy oil or pitch is mainly composed ofmonocyclic aromatic hydrocarbons, the reactivity with formaldehyde is solow that the effect thereof on the improvement of the quality of theresultant phenolic resin is likely to become poor.

The formaldehyde polymer used as the raw material in combination withthe petroleum heavy oil or the pitch in the present invention acts as across-linking agent. Specific examples of such formaldehyde polymerinclude linear polymers such as paraformaldehyde and polyoxymethylene(especially oligomer), and cyclic polymers such as trioxane.

In the polycondensation step of the process of the present invention,the petroleum heavy oil or pitch is mixed with the formaldehyde polymerin a ratio of the number of moles, in terms of formaldehyde, of theformaldehyde polymer to the number of moles, calculated from the averagemolecular weight thereof, of the petroleum heavy oil or pitch ofgenerally from 1 to 15, preferably from 2 to 12, and still preferablyfrom 3 to 11.

When the above mixing ratio of the formaldehyde polymer to the petroleumheavy oil or pitch is less than 1, the strength of a cured molding fromthe resultant modified phenolic resin would be unfavorably low. On theother hand, when the above-mentioned mixing ratio is greater than 15,the properties and yields of obtained cured moldings would no longervary, so that the use of the formaldehyde polymer in the ratio greaterthan 15 would be useless. The excess use of the formaldehyde polymer hasa possibility of hindering the lowering of the molecular weight of themodified phenolic resin in the below described molecular weight loweringstep.

Specific examples of the phenols used as the raw material in thepolycondensation step include hydroxybenzene compounds such as phenol,cresol, xylenol, resorcinol, catechol, hydroquinone, bisphenol A andbisphenol F; and hydroxynaphthalene compounds, for example,monohydroxynaphthalene compounds such as α-naphthol and β-naphthol,dihydroxynaphthalene compounds such as 1,2-dihydroxynaphthalene,1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene,2,3-dihydroxynaphthalene, 3,6-dihydroxynaphthalene,1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene,1,7-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, and2,7-dihydroxynaphthalene, and the above mentioned monohydroxynaphthaleneand dihydroxynaphthalene compounds having a substituent including analkyl group, an aromatic group, or a halogen atom, such as2-methyl-1-naphthol, 4-phenyl-1-naphthol, 1-bromo-2-naphthol, and6-bromo-2-naphthol. These compounds may be used alone or in acombination of two or more of them.

The above phenols are added to the raw material mixture until a ratio ofthe number of moles of the phenol to the number of moles, calculatedfrom the average molecular weight thereof, of the petroleum heavy oil orpitch of generally 0.3 to 5, preferably from 0.5 to 3.

When the above ratio is less than 0.3, the reactivity between thepetroleum heavy oil or pitch and the formaldehyde is lower than thatbetween the phenol and the formaldehyde, so that it may occur that asatisfactory crosslinking density cannot be attained to thereby causethe strength of a cured molding to be poor as compared with that of theconventional phenolic resin. In particular, it is likely for the curedmolding to exhibit unfavorably low impact resistance and hencebrittleness. On the other hand, when the phenols are added in a ratiogreater than 5, it is likely that the effect of the modification of thephenolic resin on the quality improvement is decreased.

In the polycondensation step of the process of the present invention, anacid catalyst is used for polycondensation of the petroleum heavy oil orpitch, the formaldehyde polymer and the phenol. Br.O slashed.nsted orLewis acids may be used as such an acid catalyst. Br.O slashed.nstedacid is preferred. Examples of Br.O slashed.nsted acids includetoluenesulfonic acid, xylenesulfonic acid, hydrochloric acid, sulfuricacid and formic acid. Of these, p-toluenesulfonic acid and hydrochloricacid are particularly preferred.

The above acid catalyst is preferably used in an amount of 0.1 to 30% byweight, still preferably 1 to 20% by weight, relative to the totalweight of the petroleum heavy oil or pitch, the formaldehyde polymer andthe phenol.

When the amount of the added acid catalyst is too small, it is likelythat the reaction time is unfavorably long, and that a satisfactoryreaction cannot be attained unless the reaction temperature is elevated.On the other hand, when the amount of the acid catalyst is greater, thereaction rate is no longer increased in proportion to the amountthereof, so that a disadvantage in view of cost is likely to beincurred.

In the polycondensation step in which the above described raw materialsand acid catalyst are employed, for example, it is preferred that theraw materials are polycondensed by gradually adding the phenol, untilthe above ratio, to a mixture containing in the above ratio thepetroleum heavy oil or pitch and the formaldehyde polymer while beingheated under agitation in the presence of the acid catalyst.

The phenol is preferably gradually added by dropping or other methods ata rate of 0.05 to 5 wt. %/min, still preferably 0.1 to 2 wt. %/min,relative to the total weight of the reaction mixture.

When the addition rate is less than 0.05 wt. %/min, the time requiredfor the addition is too long, thereby increasing cost. On the otherhand, when the addition rate exceeds 5 wt. %/min, the added phenol sorapidly reacts with free formaldehyde, that it is difficult to form ahomogeneous mixture or condensate.

The reason for this heterogeneity would be that the reactivity of theformaldehyde is much greater with the phenol than with the petroleumheavy oil or pitch, so that, unless the initial concentration of thephenol is kept low, the formaldehyde undergoes a selective reaction withthe phenol or a phenol-formaldehyde condensate formed by condensationreaction to thereby become sparingly soluble in the system.

In the polycondensation step of the process of the present invention,the time at which the phenol is added to the mixture of the petroleumheavy oil or pitch and the formaldehyde polymer is not particularlylimited. However, it is preferred that the gradual addition of thephenol be initiated in a period of from a time at which the conversionof formaldehyde, estimated from the amount of remaining freeformaldehyde, is substantially 0% to a time at which the conversion offormaldehyde is 70% or less, especially 50% or less.

When the conversion of formaldehyde exceeds 70%, the amount offormaldehyde capable of reacting with the added phenol is less, so thatthe performance of the resultant modified phenolic resin is likely to bedeteriorated.

With respect to the heating and agitation of the mixture of thepetroleum heavy oil or pitch and the formaldehyde polymer in thepresence of the acid catalyst, the reaction temperature and time aredetermined, depending on the raw material formulation, the rate ofaddition of the phenol and the properties of the resin to be obtained.Naturally, the reaction temperature and the reaction time are mutuallyaffecting factors. The heating under agitation of the above raw materialmixture in the presence of the acid catalyst may preferably be conductedat 50 to 160° C., especially 60 to 120° C. for 0.5 to 10 hr, especially1 to 5 hr.

When the production of the modified phenolic resin of the presentinvention is conducted by a batch process, the reaction can be performedin one stage, which is advantageous. Further, when the above productionis conducted by a continuous process, it is not necessary to use anapparatus having been employed in the production of the conventionalmodified phenolic resin, in which a plurality of reaction materials mustcontinuously be mixed in respective predetermined proportions and thusdifficult control is inevitable. Instead, the continuous production canbe performed by disposing a complete mixing type reactor vessel in themiddle and introducing the phenol to be added thereinto at apredetermined rate. This allows an apparatus cost to be relatively low,and ensures good operability.

In the present invention, the polycondensation reaction of the petroleumheavy oil or pitch, the formaldehyde polymer and the phenol can beperformed in the absence of a solvent. However, an appropriate solventmay be used to lower the viscosity of the reaction mixture (reactionsystem) so that uniform reaction is ensured.

Examples of such solvents include aromatic hydrocarbons, such asbenzene, toluene and xylene; halogenated aromatic hydrocarbons, such aschlorobenzene; nitro-substituted aromatic hydrocarbons, such asnitrobenzene; nitro-substituted aliphatic hydrocarbons, such asnitroethane and nitropropane; and halogenated aliphatic hydrocarbons,such as perchloroethylene, trichloroethylene and carbon tetrachloride.

In the process for producing the highly reactive low-viscosity modifiedphenolic resin according to the present invention, the modified phenolicresin obtained by the above polycondensation reaction is used to thefollowing molecular weight lowering step. In the molecular weightlowering step, the modified phenolic resin reacts with the phenol undera specific thermal conditions in the presence of an acid catalyst but inthe absence of formaldehyde polymer and other crosslinking agents, sothat the modified phenolic resin has a lowered molecular weight. In thismolecular weight lowering step, the other reaction conditions and theamounts of raw materials and catalyst are controlled so that themodified phenolic resin has a desirable viscosity by the reactionthereof with the phenol.

Besides the modified phenolic resin, the acid catalyst, unreactedmaterials, low molecular weight components, solvent, etc. may remain inthe reaction mixture obtained by the above polycondensation reaction,which affect the reaction conditions during the molecular weightlowering step and the amounts of raw materials and catalyst involved inthe reaction. For example, when the modified phenolic resin for use inthe molecular weight lowering step contains the acid catalyst, theamount of acid catalyst to be added in the above step is affected.Further, especially when the modified phenolic resin contains a largeamount of formaldehyde polymer being a crosslinking agent as anunreacted component, the polycondensation of the modified phenolicresin, the formaldehyde polymer and the phenol possibly precedes tothereby hinder the lowering of the molecular weight of the modifiedphenolic resin.

Therefore, it is preferred that the modified phenolic resin for use inthe molecular weight lowering step do not contain the acid catalyst,unreacted materials or the reaction solvent in an amount such that themolecular weight lowering reaction is hindered, especially do notcontain the acid catalyst and formaldehyde polymer, from the viewpointthat the reaction conditions during the molecular weight lowering stepare appropriately set so as to accomplish effective lowering of themolecular weight of the modified phenolic resin through the reactionthereof with the phenol.

The above modified phenolic resin may be prepared by appropriatelycontrolling the amounts of raw materials, acid catalyst and reactionsolvent employed in the polycondensation reaction or thepolycondensation reaction conditions to thereby prevent excess unreactedcomponents, acid catalyst and reaction solvent from remaining in thereaction mixture, or alternatively by appropriately purifying thereaction mixture obtained in the polycondensation reaction to therebyremove any unreacted components, low molecular weight components, acidcatalyst and reaction solvent.

The method for purifying the reaction mixture, i.e., the crude modifiedphenolic resin containing the acid catalyst, unreacted components andreaction solvent includes, for example, purification treatment (i) inwhich the reaction mixture is treated to effect precipitation with aspecific solvent to thereby remove solvent-soluble components containingunreacted components, and purification treatment (ii) in which thereaction mixture is dissolved in a specific solvent to thereby extractand remove any catalyst residue.

In the above purification treatment (i), components contained in thepetroleum heavy oil or pitch as a raw material, which have lowreactivity so as to remain in the reaction mixture in the unreacted orincompletely reacted state, and especially the formaldehyde polymer as acrosslinking agent and the solvent optionally used in thepolycondensation reaction, are removed.

This purification treatment (i) may be accomplished by putting thereaction mixture obtained in the polycondensation step, at any timeafter the production thereof, in a solvent comprising at least onecompound selected from the group consisting of aliphatic and alicyclichydrocarbons each having up to 10 carbon atoms to thereby precipitatethe principal component of the resin and remove components soluble inthe solvent, i.e., those unreacted and remaining due to incompletereaction and the solvent used in the polycondensation reaction.Aliphatic and alicyclic hydrocarbons, such as pentane, hexane, heptaneand cyclohexane, are used as such a hydrocarbon solvent forpurification. n-Hexane is particularly preferred.

In the above purification treatment (ii), the acid catalyst remaining inthe reaction mixture and the formaldehyde polymer as a crosslinkingagent are removed, thereby producing a modified phenolic resincontaining substantially no acid and no crosslinking agent. When thecatalyst residue remains in the modified phenolic resin, the amount ofacid catalyst added in the molecular weight lowering step must bedetermined taking the above acid catalyst residue into account, so thatthe control of reaction conditions becomes difficult.

The above purification treatment (ii) may be accomplished by treatingthe reaction mixture with an extraction solvent capable of dissolvingmost of the modified phenolic resin but dissolving the acid catalystused in the polycondensation of the raw materials in a solubility of 0.1or less to thereby extract and remove catalyst residue and theformaldehyde polymer as a crosslinking agent.

The extraction solvent is not particularly limited as long as it has theabove properties, which may, however, preferably be selected from amongaromatic hydrocarbons, such as benzene, toluene and xylene. Of these,toluene is particularly preferred.

In the purification treatment (ii) of the present invention, temperatureand other conditions are not particularly limited as long as the aboveperformance of the extraction solvent is fully exhibited. The reactionmixture may be put in the extraction solvent, or alternatively thesolvent may be added to the reaction mixture. Thus, the purificationtreatment (ii) can be accomplished readily and simply.

The modified phenolic resin containing substantially no acid, obtainedby the above purification treatment (ii), is generally in the form of avarnish having the resin dissolved in a solvent. The modified phenolicresin in the form of a varnish, if it is a final purified product, maybe used as it is for the next step of lowering molecular weight.Alternatively, it may be put in a solvent in which the modified phenolicresin is insoluble, such as n-hexane, to effect precipitation to therebyobtain powder of the modified phenolic resin prior to utilization.

Most of the catalyst residue remaining in the reaction mixture isremoved by the purification treatment (ii). If desired, however, themodified phenolic resin obtained by the purification treatment (ii) maybe subjected to a neutralization treatment and/or a water washingtreatment to thereby effect further removal of the catalyst residue,such as an acid, in the resin.

The neutralization treatment may be performed by adding a basicsubstance to the modified phenolic resin obtained by the purificationtreatment (ii). Examples of such basic substances include alkali metaland alkaline earth metal hydroxides, such as sodium, potassium, calciumand magnesium hydroxides, ammonia, diethylenetriamine,triethylenetetramine, aniline and phenylenediamine.

In the purification step employable for the process of the presentinvention, the purification treatments (i) and (ii) may be carried outin arbitrary sequence. However, because the modified phenolic resinobtained by the purification step (ii) is in the form of a varnish, itis preferred that the varnish be put in a solvent in which the modifiedphenolic resin is insoluble, for example, n-hexane to therebyrecrystallize and harvest powdery modified phenolic resin, from theviewpoint of handling thereof in the molecular weight lowering step.

The case in which the purification treatment (ii) is carried out afterthe purification treatment (i) is preferred in the viewpoint of theproduction cost, because the varnish modified phenol resin is used as itis in the next molecular weight lowering step.

In the process for producing the highly reactive low-viscosity modifiedphenolic resin according to the present invention, the above modifiedphenolic resin, i.e., the reaction product of the polycondensation stepis reacted as it is or after having been purified with the phenols at atemperature higher than 120° C. and not more than 200° C., andpreferably between 140° C. and 180° C. in the absence of theformaldehyde polymer and other cross-linking agents and in the presenceof the acid catalyst so that the modified phenolic resin has a loweredmolecular weight. The reaction temperature of higher than 200° C. is notpreferred, because the thermal resistance (Tg) of a molding materialusing the resultant resin is likely to be deteriorated.

In the molecular weight lowering reaction carried out in such atemperature range, it is considered that the modified phenolic resin issuffered from cleavage and dissociation of methylene bonding in itsmolecule and the phenols are bonded to dissociation terminals toincrease a phenol content of the modified phenolic resin.

There are no limitations to the amount, the type and the combination ofthe raw material and the acid catalyst, as well as the reactionconditions other than the reaction temperature used in the molecularweight lowering step, as long as it is possible to lower the viscosityof the above mentioned modified phenolic resin and to improve thereactivity thereof with the epoxy resin.

Examples of the phenols used in the molecular weight lowering stepinclude the hydroxybenzene and hydroxynaphthalene compounds described inthe polycondensation step.

In the molecular weight lowering step of the process of the presentinvention, the phenol is employed in an amount of generally at least 100parts by weight, from 100 to 300 parts by weight, more preferably from100 to 250 parts by weight, still preferably from 100 to 200 parts byweight, per 100 parts by weight of the modified phenolic resin. When theamount of the phenol is at least 100 parts by weight, the molecularweight lowering reaction is advanced to an extent sufficient forobtaining the desired effect. However, the use of the phenol in excesswould result in the remaining of a large amount of unreacted phenol,thereby increasing the cost for posttreatment.

The acid catalyst is added preferably in an amount of 0.1 to 15 parts byweight, still preferably from 0.2 to 10 parts by weight per 100 parts byweight of the modified phenolic resin.

In the molecular weight lowering step, the reaction may be carried outin the absence or presence of a reaction solvent. The reaction solventis not particularly limited as long as it does not hinder the abovemolecular weight lowering reaction. For example, the solvents availablefor the polycondensation and alcohols such as methyl alcohol, ethylalcohol, buthyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol,nonyl alcohol and decyl alcohol may be used in the molecular weightlowering step. The solvent is used preferably in the amount of 0-300parts by weight relative to 100 parts by weight of the modified phenolicresin.

The reaction temperature is not lower than a certain reactiontemperature, typically from 120 to 200° C., and preferably from 140 to180° C. The reaction time is not limited specifically and may be, forexample, from 15 minutes to 2.0 hours, and preferably from 30 minutes to2.0 hours.

The highly reactive low-viscosity modified phenolic resin obtained as aresult of the molecular weight lowering step is lower in (a) numberaverage molecular weight and in (c) resin melt viscosity than themodified phenolic resin obtained by the polycondensation step.

According to the process of the present invention, there is provided ahighly reactive modified phenolic resin having the number averagemolecular weight of from 350 to 650 and the resin melt viscositymeasured at 150° C. of from 0.2 to 4.5 poises.

More specifically, the melt viscosity of the highly reactivelow-viscosity modified phenolic resin can be lowered considerably whenthe hydroxybenzene compound is used as the phenols in the molecularweight lowering step. In this event, there is provided a highly reactivelow-viscosity modified phenolic resin having the number averagemolecular weight of from 350 to 450, and particularly from 350 to 400,and the resin melt viscosity measured at 150° C. of from 0.2 to 3.0poises, and particularly from 0.2 to 2.0 poises.

When the hydroxynaphthalene compound is used as the phenols in themolecular weight lowering step, the resultant highly reactivelow-viscosity modified phenolic resin is apt to have a higher meltviscosity than that obtained with the hydroxybenzene compound. However,the thermal resistance and the resistance to the moisture absorption ismore improved than the case of using the hydroxybenzene compound. Inthis event, there is provided a highly reactive modified phenolic resinsuperior in thermal resistance and resistance to moisture absorptionhaving the number average molecular weight of from 350 to 650, andparticular from 350 to 600, and the resin melt viscosity measured at150° C. of from 1.0 to 4.5 poises, and particularly from 1.0 to 4.0poises.

The highly reactive low-viscosity modified phenolic resin has a lowresin melt viscosity and thus good moldability and is highly reactivewith the epoxy resin. Therefore, the highly reactive low-viscositymodified phenolic resin can provide a molding material having aconsiderably low moisture absorption, as well as good dimensionalstability and mechanical properties including strength, when combinedwith the epoxy resin.

As mentioned above, the present inventors discloses in Japanese PatentLaid-Open Publication No. 7(1995)-252339 a molecular weight loweringstep which is carried out at a temperature not higher than 120° C. tocause dissociation of the acetal bonding and/or methylene ether bondingin the resin molecules.

However, the molecular weight lowering step of the present invention iscarried out at a higher temperature to allow production of a highlyreactive modified phenolic resin having a lower viscosity of from 0.2 to4.5 poises, which cannot be achieved by the conventional processes. Thereason would be that the molecular weight lowering step carried out atthe higher temperature causes cleavage and dissociation of regions orsites other than the acetal bonding and/or methylene ether bonding,i.e., cleavage and dissociation of methylene bonding in the modifiedphenolic resin molecules.

It was revealed that the highly reactive low-viscosity modified phenolicresin obtained according to the process of the present inventionexhibits a considerably low moisture absorption when used as a moldingmaterial in combination with the epoxy resin as described later. Suchmolding materials are advantageously employed for articles in whichcorrosion of metal portions and deterioration of the dimensionalstability are undesirable. In addition, it is expected that the thermalresistance and the resistance to moisture absorption of the moldingmaterial is further improved by means of producing the highly reactivelow-viscosity modified phenolic resin with using the hydroxynaphthalenecompound in the molecular weight lowering step.

The highly reactive low-viscosity modified phenolic resin obtained bysuch molecular weight lowering step may be used as it is for variousapplications. However, there is a possibility of the unreactedcomponents and the acid catalyst remained in the resin. Accordingly, itis preferable to remove the unreacted components and the acid catalystsin a similar manner by using the solvent described in the purification(i) and (ii) of the modified phenolic resin or by means of purificationwith a different solvent. Examples of the solvent suitably used for thepurification of the highly reactive low-viscosity modified phenolicresin include toluene; mixed solvents of toluene and alcohols such asethyl alcohol and methyl alcohol; and mixed solvents of toluene andketone such as acetone, tetrahydrofurane, methyl ethyl ketone, andmethyl isobutyl ketone.

It is preferred that the highly reactive low-viscosity modified phenolicresin be subjected to a washing treatment using a mixed solution ofdistilled water and isopropyl alcohol, if necessary, after the unreactedcomponents such as phenols and the acid catalyst are extracted by usingthe above mentioned solvent.

If there still remains the unreacted phenols after such treatment, theymay be removed by means of distillation with water vapor. The unreactedphenols may also be removed by means of introducing nitrogen under heatinstead of the vapor distillation. These methods may be carried out incombination.

It is also preferred that the highly reactive low-viscosity modifiedphenolic resin be desolvated or precipitated with an aliphatic oralicyclic hydrocarbon having up to 10 carbon atoms, or a mixturethereof, after the unreacted components and the acid catalyst areremoved therefrom. The hydrocarbon solvent includes the solventdescribed in the purification (i) for the modified phenolic resin. Amongthem, n-hexane is particularly preferable.

The purification as described above removes the acid catalyst, unreactedmaterials and reaction solvent remaining in the resin to thereby providea highly reactive modified phenolic resin which contains substantiallyno acid, thereby exhibiting no corrosive action to metals and which isimproved in the reactivity to an epoxy resins, thereby having improvedthermal resistance and dimensional stability. The terminology"containing substantially no acid" used herein means that either an acidor the like is completely absent, or an extremely small amount thereofremains which however does not exhibit any significant corrosive actionto metals.

The molding material based on the modified phenolic resin according tothe present invention comprises (B) an epoxy resin together with (A) thehighly reactive low-viscosity modified phenolic resin which is obtainedby the process of the present invention and has the resin melt viscosityof from 0.2 to 4.5 poises, and particularly from 0.2 to 3.0 poises orfrom 1.0 to 4.5 poises. In the molding material based on the modifiedphenolic resin according to the present invention, the highly reactivelow-viscosity modified phenolic resin (A) may be composed of a resin, orat least two resins, for example, the highly reactive low-viscositymodified phenolic resins made by using the hydroxybenzene compound inthe molecular weight lowering step and made by using thehydroxynaphthalene compound in the molecular weight lowering step.

The epoxy resin generally exhibits less molding shrinkage, excellentthermal, abrasion and chemical resistance, and high electricalinsulating property. The epoxy resin may optionally be employed incombination with a curing agent and/or curing accelerator (C).

Various epoxy resins are available, which include, for example, glycidylether, glycidyl ester, glycidylamine, mixed and alicyclic epoxy resins.

In particular, examples of the glycidyl ether (based on phenol) epoxyresins include bisphenol A, biphenyl, bisphenol F, tetrabromobisphenolA, tetraphenylolethane, phenolic novolak and o-cresol novolak epoxyresins.

Examples of the glycidyl ether (based on alcohol) epoxy resins includepolypropylene glycol and hydrogenated bisphenol A epoxy resins.

Examples of the glycidyl ester epoxy resins include hexahydrophthalicanhydride and dimer acid epoxy resins.

Examples of the glycidylamine epoxy resins includediaminodiphenylmethane, isocyanuric acid and hydantoinic acid epoxyresins.

Examples of the mixed epoxy resins include p-aminophenol andp-oxybenzoic acid epoxy resins. Of the above epoxy resins, bisphenol A,biphenyl, glycidylamine and phenolic novolak epoxy resins are preferred.The above epoxy resins may also be used in combination.

With respect to the ratio at which the highly reactive modified phenolicresin of the present invention is blended with the epoxy resin, it isgenerally preferred that the modified phenolic resin be blended with theepoxy resin at a ratio of 10/90 to 90/10 (parts by weight), especially20/80 to 80/20 (parts by weight).

Various conventional curing agents and accelerators used for curingepoxy resins can be employed as a curing agent and/or accelerator (C) tobe incorporated in the molding material based on the modified phenolicresin according to the present invention. Examples of such curing agentsinclude cyclic amines, aliphatic amines, polyamides, aromatic polyaminesand acid anhydrides.

In particular, examples of suitable cyclic amines includehexamethylenetetramine, and examples of suitable aliphatic aminesinclude diethylenetriamine, triethylenetetramine,tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperamine,isophoronediamine, bis(4-amino-3-methylcyclohexyl)methane andmenthanediamine.

Examples of the polyamides include condensates of a fatty acid fromvegetable oil (dimer or trimer acid) and an aliphatic polyamine.

Examples of the aromatic polyamines include m-phenylenediamine,4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone andm-xylylenediamine.

Examples of the acid anhydrides include phthalic anhydride,tetrahydrophthalic anhydride, hexahydrophthalic anhydride, trimelliticanhydride, pyromellitic anhydride, benzophenonetetracarboxylicanhydride, chlorendic anhydride, dodecenylsuccinic anhydride,methyltetrahydrophthalic anhydride andmethylendomethylenetetrahydrophthalic anhydride.

Examples of the curing accelerators include diazabicycloalkenes such as1,8-diazabicyclo(5,4,0)undecene-7 and derivatives thereof; tertiaryamines such as triethylenediamine, benzyldimethylamine, triethanolamine,dimethylaminoethanol and tris(dimethylaminomethyl)phenol; imidazolessuch as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole,2-phenyl-4-methylimidazole and 2-heptadecylimidazole; organophosphinessuch as tributylphosphine, methyldiphenylphosphine andtriphenylphosphine; tetrasubstituted-phosphoniumtetra-substituted-borates such as tetraphenylphosphoniumtetraphenylborate; tetraphenylborates such as 2-ethyl-4-methylimidazolyltetraphenylborate and N-methylmorpholinyl tetraphenylborate; Lewis acidssuch as boron trifluoride/amine complex; Lewis bases such asdicyanodiamide and adipodihydrazide; and polymercaptans andpolysulfides. The above curing agents and curing accelerators may beemployed either individually or in combination.

The molding material based on (A) the highly reactive low-viscositymodified phenolic resin and (B) the epoxy resin exhibits a low moistureabsorption. This moisture absorption is lower than those of theconventional highly reactive modified phenolic resins. Such moldingmaterials may advantageously be used for articles such as the electricaland electronic parts as well as the semiconductor sealers wherecorrosion of metal portions and deterioration of the dimensionalstability are undesirable.

The molding material based on the modified phenolic resin according tothe present invention may comprise an inorganic filler (D), in additionto the highly reactive modified phenolic resin (A), the epoxy resin (B)and the optionally added curing agent and/or curing accelerator (C).

The strength and dimensional stability of the obtained molding canfurther be improved by the addition of the inorganic filler (D) to themolding material.

Various conventional inorganic fillers having been used as an inorganicfiller or reinforcement for plastic materials may be used as theinorganic filler (D) in the present invention. Examples of suchinorganic fillers include reinforcing fibers, such as glass, carbon,phosphor and boron fibers; hydrated metal oxides, such as aluminum andmagnesium hydroxides; metal carbonates, such as magnesium and calciumcarbonates; metal borates, such as magnesium borate; and inorganicreinforcements, such as silica, mica and fused silica.

The amount of added inorganic filler (D) is not particularly limited.However, it is preferred that 20 to 800 parts by weight, especially 50to 600 parts by weight of the inorganic filler be added per 100 parts byweight of the highly reactive modified phenolic resin.

Moreover, if desired, the molding material based on the modifiedphenolic resin according to the present invention may further compriseadditives, including internal release agents, such as silicone andwaxes, coupling agents, flame retarders, light stabilizers,antioxidants, pigments and extenders.

The molding material based on the modified phenolic resin according tothe present invention as described above is prepared by mixing togetherthe highly reactive low-viscosity modified phenolic resin (A) and theepoxy resin (B), optionally together with the curing agent and/or curingaccelerator (C), the inorganic filler (D) and various additives, andused for forming various moldings.

In the present invention, the sequence in which the highly reactivelow-viscosity modified phenolic resin (A), the epoxy resin (B) andoptionally added components such as the curing agent (C) are blended, isnot particularly limited. For example, a powdery molding compound may beobtained by first blending a highly reactive modified phenolic resinwith an epoxy resin, secondly adding a curing agent (curing accelerator)to the blend, followed by effective kneading, and finally, if desired,adding an inorganic filler and additives, followed by kneading.

In particular, the above compound may be produced by the followingsequence of operations:

(1) blending a highly reactive low-viscosity modified phenolic resinwith an epoxy resin in an automatic mortar at room temperature;

(2) adding to the resultant blend other additives such as a curing agentand wax, followed by blending;

(3) adding to the resultant blend an inorganic filler, followed byblending; and

(4) further effecting blending by means of rolls heated at 80 to 90° C.for 3 to 10 min, cooling to room temperature and pulverizing to therebyobtain the desired compound.

In this sequence of operations, the additions of the inorganic fillerand the other additives are separately carried out after the blending ofthe highly reactive low-viscosity modified phenolic resin and the epoxyresin. This is not critical, and the additions of the additives may beconducted at an arbitrary time.

The molding material based on the highly reactive modified phenolicresin according to the present invention can be molded by variousconventional molding means, including, for example, compression,injection, extrusion, transfer and casting molding techniques.

In particular, when the molding material based on modified phenolicresin according to the present invention is formed into a molding bytransfer molding technique, such molding conditions are preferablyselected that the molding temperature is in the range of from 120 to200° C., the injection pressure is in the range of from 5 to 300Kgf/cm², especially 20 to 300 Kgf/cm², the clamp pressure is in therange of from 50 to 250 Kgf/cm² and the molding time is in the range offrom 1 to 10 min.

The resultant molding is preferably subjected to a postcure comprisingheating at 150 to 300° C. for 0.5 to 24 hr.

The postcure further improves the thermal resistance of the molding.

The molding obtained from the molding material based on the modifiedphenolic resin according to the present invention is excellent inresistances to moisture and high temperature, as well as electricalinsulation properties and mechanical strength, and has, for example, thefollowing properties:

    ______________________________________    Flexural strength                   room temp- 8-22 kgf/mm.sup.2                   erature                   150° C.                              3-14 kgf/mm.sup.2    Flexural modulus                   room temp- 400-2000 kgf/mm.sup.2                   erature                   150° C.                              40-1500 kgf/mm.sup.2    Glass transition          120-260° C.    temperature (° C.)    Thermal deformation       190-300° C. or    temperature    higher    Insulation resist-                   ordinary   1.8 × 10.sup.14 -    ance           state      5.0 × 10.sup.14 Ω                   after      3.0 × 10.sup.13 -                   boiling    2.0 × 10.sup.14 Ω    ______________________________________

The molding material based on the modified phenolic resin according tothe present invention has the improved reactivity of the modifiedphenolic resin with the epoxy resin, so that the molded articlesproduced therefrom have improved mechanical properties including thedimensional stability and the thermal stability. The highly reactivelow-viscosity modified phenolic resin used has a low viscosity and thusgood moldability, and significantly low moisture absorption. In themolding material based on the modified phenolic resin according to thepresent invention, the possible corrosive effect on the metals can bereduced or eliminated by using the modified phenolic resin containingsubstantially no acid. By adding the inorganic filler, it is possible tofurther improve the mechanical strength and the electrical insulationproperties of the resultant molded articles.

Accordingly, the molded article made of the material based on themodified phenolic resin is useful as materials of the electrical andelectronic parts and components such as printed boards, insulatingmaterials, and sealants, where the moisture absorption is undesirableand on which stringent requirements are imposed regarding thedimensional stability, the thermal resistance, and the moldability. Inaddition, it is particularly useful as the semiconductor sealers onwhich improvements of thermal resistance, dimensional stability to copewith stress damaging attributed to a higher degree of integration, andmoisture absorption are demanded.

EFFECT OF THE INVENTION

According to the process for producing the highly reactive low-viscositymodified phenolic resin of the present invention, the modified phenolicresin is produced by the above mentioned polycondensation and molecularweight lowering steps, so that there is provided a highly reactivelow-viscosity modified phenolic resin having a high reactivity with theepoxy resin and an especially lower resin melt viscosity.

The process of the present invention can further lower the meltviscosity of the highly reactive low-viscosity modified phenolic resinby using the hydroxybenzene compound as the phenols in the molecularweight lowering step. In addition, the thermal resistance and resistanceto moisture absorption of the resultant highly reactive low-viscositymodified phenolic resin can be further improved by using thehydroxynaphthalene compound as the phenols in the molecular weightlowering step.

Furthermore, according to the process for producing the highly reactivelow-viscosity modified phenolic resin of the present invention, thehighly reactive low-viscosity modified phenolic resin obtained in themolecular weight reduction step is purified to remove any unreactedcomponents and acid catalyst to provide the highly reactivelow-viscosity modified phenolic resin having significantly low resinmelt viscosity and high reactivity with the epoxy resin, as well ashaving no corrosive effect on metals because it contains substantiallyno acid.

The molding material based on the modified phenolic resin of the presentinvention comprises the highly reactive low-viscosity modified phenolicresin obtained by the process of the present invention and the epoxyresin, and has considerably low moisture absorption and good thermalresistance and moldability, with which it is possible to provide amolding material for the molding articles having superior mechanicalproperties including the dimensional stability, in particular,especially to provide the electrical and electronic parts and thesemiconductor sealers.

EXAMPLE

The present invention will further be illustrated with reference to thefollowing Examples, which should not be construed as limiting the scopeof the invention.

In the following Examples, the parts are by weight, unless otherwisespecified. The characteristics of stock oil as a raw material forpolycondensation are indicated in Table 1. The stock oil is one obtainedby distilling bottom oil produced by fluid catalytic cracking (FCC) ofvacuum gas oil.

                  TABLE 1    ______________________________________    Average Molecular Weight                      271    Boiling Point (° C.)                      241.5-466.5    Ratio of Aromatic 0.65    Hydrocarbon (fa)    Ratio of Hydrogen of                      28    Aromatic Ring (Ha) (%)    ______________________________________     Note:     (1) Average molecular weight: value measured according to the vapor     pressure osmometry.     (2) Boiling point: value of ° C. in terms of the atmospheric     pressure, measured according to ASTM D1160.

In the following examples, the number average molecular weight, thereactivity with an epoxy resin (determined on the basis of gelationtime; the shorter gelation time means the higher reactivity), and theresin melt viscosity were measured by using the following apparatus ormeasuring methods.

Number Average Molecular Weight

Measured by using HLC-8020 GPC apparatus (Column; TSK gel 3000 HHR+TSKgel 2000 HHR, calculated using polystyrene as a standard substance:Manufactured by TOSOH Co., Ltd. )

Viscosity Measurement

Measured by the ICI cone plate viscometer manufactured by ICI Co.

Gelation Time

Measured at 170° C. in accordance with Japanese Industrial Standard(JIS) K 6910.

Glass Transition Temperature

Method: dynamic modulus of viscoelasticity

Apparatus: DVE RHEOSPECTOLER DVE-4V manufactured by Rheorogy Co.

Loading: tensile loading

Frequency: 10 Hz

Rate of temperature increase: 5° C./min.

Dynamic measurement displacement: ±5+10⁻⁴ cm

Test piece: 4 mm in width, 1 mm in thickness, and 30 mm in span

OH Equivalent

Measured according to acetyl chloride method

Example 1

Polycondensation Step

334 g of stock oil having the characteristics shown in Table 1, 370 g ofparaformaldehyde, 137 g of p-toluenesulfonic acid monohydrate and 678.5g of p-xylene were charged into a glass reactor, and the temperaturethereof was elevated to 95° C. under agitation. The mixture was held at95° C. for 1 hour. Subsequently, 209 g of phenol was added dropwise tothe mixture at a rate of 1.3 g/min. After completion of the dropwiseaddition of phenol, agitation was continued for additional 15 minutes toeffect reaction. Next, the reaction mixture was poured into 3,300 g ofn-hexane to precipitate a reaction product. The precipitate was thenfiltered to remove unreacted components and reaction solvent. Theresultant precipitate was washed with 1,600 g of n-hexane and dried invacuum to obtain a crude modified phenolic resin containing an acid.

This modified phenolic resin was dissolved into a 10-fold weight oftoluene. Insoluble substances mainly composed of p-toluenesulfonic acidmonohydrate was filtered off. The resultant toluene solution of theresin was concentrated to a resin concentration of 50% by weight toobtain a modified phenolic resin in the form of vanish. Furthermore, asmall amount of triethylenetetramine was added thereto forneutralization. The resultant modified phenolic resin in the form ofvanish was poured into a 3.3-fold weight of n-hexane to precipitate theresin. The precipitated resin was filtered and dried in vacuum to obtain580 g of powdery modified phenolic resin.

Molecular Weight Lowering Step

100 g of the resultant powdery modified phenolic resin, 200 g of phenol,and 5 g of p-toluenesulfonic acid were charged into a 1-liter glassreactor. The mixture was heated to the temperature of 120° C. whilestirring at a rate of 250-350 rpm. The mixture was allowed to react at120° C. for 90 minutes to obtain a reaction product. The resultantreaction product was poured into 400 ml of mixed solution oftoluene/methyl isobutyl ketone (mixing ratio of 7/3) and dissolvedtherein. The resultant resin mixed solution was washed with distilledwater to remove the acid, and the mixed solvent was then removed byusing an evaporator to obtain 182 g of a highly reactive low-viscositymodified phenolic resin.

The number average molecular weight, the viscosity at 150° C., and thehydroxyl equivalent were measured on the resultant highly reactivelow-viscosity modified phenolic resin. The results are shown in Table 2along with reaction conditions in the molecular weight lowering stepincluding the reaction temperature.

Examples 2-6

Example 1 was repeated except that the reaction conditions for themolecular weight lowering step were changed as shown in Table 2 toobtain a highly reactive low-viscosity modified phenolic resin in theyields shown in Table 2.

The number average molecular weight, the viscosity at 150° C., and thehydroxyl equivalent were measured on the resultant highly reactivelow-viscosity modified phenolic resin. The results are shown in Table 2.

Example 7

100 g of powdery modified phenolic resin obtained in thepolycondensation step in Example 1, 200 g of o-cresol, and 5 g ofp-toluenesulfonic acid were charged into a 1-liter glass reactor. Themixture was heated to the temperature of 140° C. while stirring at arate of 250-350 rpm. The mixture was allowed to react at 140° C. for 90minutes to obtain a reaction product.

The resultant reaction product was introduced into 400 ml of mixedsolution of toluene/methyl isobutyl ketone (mixing ratio of 7/3) anddissolved therein. The resultant resin mixed solution was washed withdistilled water to remove the acid, and the mixed solvent was thenremoved by using an evaporator to obtain 192 g of a highly reactivelow-viscosity modified phenolic resin based on o-cresol.

The number average molecular weight, the viscosity at 150° C., and thehydroxyl equivalent were measured on the resultant highly reactivelow-viscosity modified phenolic resin. The results are shown in Table 2.

Example 8

Example 7 was repeated except that the reaction conditions for themolecular weight lowering step were changed as shown in Table 2 toobtain a highly reactive low-viscosity modified phenolic resin in theyields shown in Table 2.

The number average molecular weight, the viscosity at 150° C., and thehydroxyl equivalent were measured on the resultant highly reactivelow-viscosity modified phenolic resin. The results are shown in Table 2.

Example 9

Example 7 was repeated except that m-cresol was used in place ofo-cresol as the hydroxybenzene compound in the molecular weight loweringstep to obtain a highly reactive low-viscosity modified phenolic resinbased on m-cresol in the yields shown in Table 2.

The number average molecular weight, the viscosity at 150° C., and thehydroxyl equivalent were measured on the resultant highly reactivelow-viscosity modified phenolic resin. The results are shown in Table 2.

Example 10

200 g of modified phenolic resin in the form of vanish (resinconcentration of 50%) obtained in the polycondensation step in Example1, 200 g of phenol, and 5 g of p-toluenesulfonic acid were charged intoa 1-liter glass reactor. The mixture was heated to the temperature of160° C. while stirring at a rate of 250-350 rpm. The mixture was allowedto react at 160° C. for 90 minutes to obtain a reaction product.

The resultant reaction product was introduced into 400 ml of mixedsolution of toluene/methyl isobutyl ketone (mixing ratio of 7/3) anddissolved therein. The resultant resin-mixed solution was washed withdistilled water to remove the acid, and the mixed solvent was thenremoved by using an evaporator to obtain 200 g of a highly reactivelow-viscosity modified phenolic resin.

The number average molecular weight, the viscosity at 150° C., and thehydroxyl equivalent were measured on the resultant highly reactivelow-viscosity modified phenolic resin. The results are shown in Table 2.

Comparative Example 1

100 g of powdery modified phenolic resin obtained in thepolycondensation step in Example 1, 200 g of phenol, and 5 g ofp-toluenesulfonic acid were charged into a 1-liter glass reactor. Themixture was heated to the temperature to 95° C. while stirring at a rateof 250-350 rpm. The mixture was allowed to react at 95° C. for 90minutes to obtain a reaction product.

The resultant reaction product was introduced into 400 ml of mixedsolution of toluene/methyl isobutyl ketone (mixing ratio of 7/3) anddissolved therein. The resultant resin-mixed solution was washed withdistilled water to remove the acid, and the mixed solvent was thenremoved by using an evaporator to obtain 175 g of resultant modifiedphenolic resin.

The number average molecular weight, the viscosity at 150° C., and thehydroxyl equivalent were measured on the resultant modified phenolicresin. The results are shown in Table 2.

Example 11

9.17 parts by weight of highly reactive low-viscosity modified phenolicresin obtained in Example 3 and 14.89 parts by weight of biphenyl epoxyresin (trade name; YX4000H, produced by Yuka Shell Epoxy Co., Ltd.) weremixed and agitated by using an automatic mortar at a room temperature.Then, 0.49 parts by weight of triphenylphosphine (TPP) was added to themixture as a curing accelerator to obtain a resin mixture containing acuring accelerator-containing resin mixture.

The gelation time of the curing accelerator-containing resin mixture wasmeasured and is shown in Table 3.

0.25 parts by weight of carnauba wax was added to and mixed with theresultant curing accelerator-containing resin mixture. Then, 0.20 partsby weight of carbon black and 75 parts by weight of fused silica (tradename; CRS1102-GT200T, produced by Tatsumori Co., Ltd.) as inorganicfillers were added to and mixed with the mixture. The resultant mixturewas mixed for additional 3-10 minutes by using rolls heated at 80-90° C.and was then cooled to a room temperature. The resultant mixture wasthen pulverized to obtain a compound. The formulation of this compoundis shown in Table 3.

The resultant compound was subjected to transfer molding conducted at175° C. for 90 seconds and was postcured at 175° C. for additional 6hours to obtain a molded article.

The Shore hardness, the glass transition temperature, the flexuralproperties, and the moisture absorption were measured on the resultantmolded article just after the molding. The results are shown in Table 3.

Examples 12-17

Example 11 was repeated except that the highly reactive low-viscositymodified phenolic resin obtained in Example 3 was replaced with thehighly reactive low-viscosity modified phenolic resin obtained in eachof Examples 4-10, and that the modified phenolic resin and the epoxyresin were blended in the ratio shown in Table 3 to obtain a curingaccelerator-containing resin mixture, a compound, and a molded article.

The gelation time of the curing acceleration-containing resin mixture ofthe curing acceleration-containing mixture and the physical properties(the Shore hardness, the glass transition temperature, the flexuralproperties, and the moisture absorption just after the molding of themolded article) of the molded article were measured on the resultantmolded article. The results are shown in Table 3.

Comparative Example 2

Example 11 was repeated except that the highly reactive low-viscositymodified phenolic resin obtained in Example 3 was replaced with themodified phenolic resin obtained in Comparative Example 1 to obtain acuring accelerator-containing resin mixture, a compound, and a moldedarticle.

The gelation time of the curing acceleration-containing resin mixtureand the physical properties (the Shore hardness, the glass transitiontemperature, the flexural Properties, and the moisture absorption justafter the molding) of the molded article were measured. The results areshown in Table 3.

Example 18

9.39 parts by weight of highly reactive low-viscosity modified phenolicresin obtained in Example 1 and 14.91 parts by weight of o-cresolnovolak epoxy resin (trade name; EOCN1020, produced by Nippon KayakuKabushiki Kaisha) were mixed and agitated by using an automatic mortarat a room temperature. Then, 0.25 parts by weight of triphenylphosphine(TPP) was added to the mixture as a curing accelerator to obtain acuring accelerator-containing resin mixture.

The gelation time of the curing accelerator-containing resin mixture wasmeasured and is shown in Table 4.

0.25 parts by weight of carnauba wax was added to and mixed with theresultant curing accelerator-containing resin mixture. Then, 0.20 partsby weight of carbon black and 75 parts by weight of fused silica (tradename; CRS1102-GT200T, produced by Tatsumori Co., Ltd.) as inorganicfillers were added to and mixed with the mixture. The resultant mixturewas mixed for additional 3-10 minutes by using rolls heated at 80-90° C.and was then cooled to a room temperature. The resultant mixture wasthen pulverized to obtain a compound. The formulation of this compoundis shown in Table 4.

The resultant compound was subjected to transfer molding conducted at175° C. for 90 seconds and was postcured at 175° C. for additional 6hours to obtain a molded article.

The Shore hardness, the glass transition temperature, the flexuralproperties, and the moisture absorption were measured on the resultantmolded article just after the molding. The results are shown in Table 4.

Examples 19-23

Example 18 was repeated except that the highly reactive low-viscositymodified phenolic resin obtained in Example 1 was replaced with thehighly reactive low-viscosity modified phenolic resin obtained in eachof Examples 2-10, and that the modified phenolic resin and the epoxyresin were blended in the ratio shown in Table 4 to obtain a curingaccelerator-containing resin mixture, a compound, and a molded article.

The gelation time of the curing accelerator-containing resin mixture andthe physical properties (the Shore hardness, the glass transitiontemperature, the flexural properties, and the moisture absorption justafter the molding) of the molded article were measured. The results areshown in Table 4.

Comparative Example 3

Example 18 was repeated except that the highly reactive low-viscositymodified phenolic resin obtained in Example 1 was replaced with themodified phenolic resin obtained in Comparative Example 1 to obtain acuring accelerator-containing resin mixture, a compound, and a moldedarticle.

The gelation time of the curing accelerator-containing resin mixture andthe physical properties (the Shore hardness, the glass transitiontemperature, the flexural properties, and the moisture absorption justafter the molding) of the molded article were measured. The results areshown in Table 4.

Example 24 Molecular Weight Lowering Step

100 g of powdery modified phenolic resin obtained in thepolycondensation step in Example 1 and 250 g of α-naphthol were chargedinto a 1-liter glass reactor. The mixture was heated to the temperatureof 120° C. while stirring at a rate of 250-350 rpm. 5 g ofp-toluenesulfonic acid dissolved in 5 g of 1-butanol was added dropwiseto the mixture and the mixture was allowed to react at 120° C. for 120minutes to obtain a reaction product.

The resultant reaction product was introduced into 800 ml of methylisobutyl ketone and dissolved therein. The resultant resin mixedsolution was washed with distilled water to remove the acid, and thesolvent was then removed by using an evaporator.

The resultant crude highly reactive modified phenolic resin wasdistilled by water vapor at 160-170° C. and unreacted α-naphthol wasremoved therefrom by means of introducing nitrogen at the sametemperature to obtain 230 g of highly reactive low-viscosity modifiedphenolic resin.

The number average molecular weight, the viscosity at 150° C., and thehydroxyl equivalent were measured on the resultant highly reactivelow-viscosity modified phenolic resin. The results are shown in Table 5along with reaction conditions for the molecular weight lowering stepincluding the reaction temperature.

Examples 25-27

Example 24 was repeated except that the reaction conditions for themolecular weight lowering step were changed as shown in Table 5 toobtain a highly reactive low-viscosity modified phenolic resin in theyields shown in Table 5.

The number average molecular weight, the viscosity at 150° C., and thehydroxyl equivalent were measured on the resultant highly reactivelow-viscosity modified phenolic resin. The results are shown in Table 5.

Example 28

100 g of powdery modified phenolic resin obtained in thepolycondensation step in Example 1, 101 g of α-naphthol, 132 g ofphenol, and 5 g of p-toluenesulfonic acid were charged into a 1-literglass reactor. The mixture was heated to the temperature of 160° C.while stirring at a rate of 250-350 rpm. The mixture was allowed toreact at 160° C. for 60 minutes to obtain a reaction product.

The resultant reaction product was introduced into 800 ml of mixedsolution of toluene/methyl isobutyl ketone (mixing ratio of 7/3) anddissolved therein. The resultant resin-mixed solution was washed withdistilled water to extract and remove the acid, and the mixed solventwas then removed by using an evaporator. The resultant crude highlyreactive modified phenolic resin was distilled by water vapor at160-170° C. and unreacted α-naphthol and phenol were removed therefromby means of introducing nitrogen at the same temperature to obtain 220 gof highly reactive low-viscosity modified phenolic resin.

The number average molecular weight, the viscosity at 150° C., and thehydroxyl equivalent were measured on the resultant naphthol highlyreactive low-viscosity modified phenolic resin. The results are shown inTable 5.

Example 29

100 g of powdery modified phenolic resin obtained in thepolycondensation step in Example 1 and 200 g of β-naphthol were chargedinto a 1-liter glass reactor. The mixture was heated to the temperatureof 140° C. while stirring at a rate of 250-350 rpm. 5 g ofp-toluenesulfonic acid dissolved in 1-butanol was added dropwise to themixture and the mixture was allowed to react at 140° C. for 120 minutesto obtain a reaction product.

The resultant reaction product was introduced into 800 ml of methylisobutyl ketone and dissolved therein. The resultant resin mixedsolution was washed with distilled water to extract and remove the acid,and the solvent was then removed by using an evaporator.

The resultant crude highly reactive modified phenolic resin wasdistilled by water vapor at 160-170° C. and unreacted β-naphthol wasremoved therefrom by means of introducing nitrogen at the sametemperature to obtain 220 g of highly reactive low-viscosity modifiedphenolic resin.

The number average molecular weight, the viscosity at 150° C., and thehydroxyl equivalent were measured on the resultant highly reactivelow-viscosity modified phenolic resin. The results are shown in Table 5.

Example 30

200 g of modified phenolic resin in the form of vanish (resinconcentration of 50%) obtained in the polycondensation step in Example 1and 250 g of α-naphthol were charged into a 1-liter glass reactor. Themixture was heated to the temperature of 120° C. while stirring at arate of 250-350 rpm. 5 g of p-toluenesulfonic acid dissolved in 5 g of1-butanol was added dropwise to the mixture and the mixture was allowedto react at 120° C. for 120 minutes to obtain a reaction product.

The resultant reaction product was introduced into 800 ml of methylisobutyl ketone and dissolved therein. The resultant resin-mixedsolution was washed with distilled water to extract and remove the acid,and the solvent was then removed by using an evaporator.

The resultant crude highly reactive modified phenolic resin wasdistilled by water vapor at 160-170° C. and unreacted α-naphthol wasremoved therefrom by means of introducing nitrogen at the sametemperature to obtain 230 g of highly reactive low-viscosity modifiedphenolic resin.

The number average molecular weight and the viscosity at 150° C., andthe hydroxyl equivalent were measured on the resultant highly reactivelow-viscosity modified phenolic resin. The results are shown in Table 5.

Example 31

11.71 parts by weight of highly reactive low-viscosity modified phenolicresin obtained in Example 24 and 12.35 parts by weight of biphenyl epoxyresin (trade name; YX4000H, produced by Yuka Shell Epoxy Co., Ltd.) weremixed and agitated by using an automatic mortar at a room temperature.Then, 0.49 parts by weight of triphenylphosphine (TPP) was added to themixture as a curing accelerator to obtain a curing acceleratorcontaining resin mixture.

The gelation time of the curing accelerator-containing resin mixture wasmeasured and is shown in Table 6.

0.25 parts by weight of carnauba wax was added to and mixed with theresultant curing accelerator-containing resin mixture. Then, 0.20 partsby weight of carbon black and 75 parts by weight of fused silica (tradename; CRS1102-GT200T, produced by Tatsumori Co., Ltd.) as inorganicfillers were added to and mixed with the mixture. The resultant mixturewas mixed for additional 3-10 minutes by using rolls heated at 80-90° C.and was then cooled to a room temperature. The resultant mixture wasthen pulverized to obtain a compound. The formulation of this compoundis shown in Table 6.

The resultant compound was subjected to transfer molding conducted at175° C. for 90 seconds and was postcured at 175° C. for additional 6hours to obtain a molded article.

The Shore hardness, the glass transition temperature, the flexuralproperties, and the moisture absorption were measured on the resultantmolded article just after the molding. The results are shown in Table 6.

Examples 32-37

Example 31 was repeated except that the highly reactive low-viscositymodified phenolic resin obtained in Example 24 was replaced with thehighly reactive low-viscosity modified phenolic resin obtained in eachof Examples 25-30, and that the modified phenolic resin and the epoxyresin were blended in the ratio shown in Table 6 to obtain a curingaccelerator-containing resin mixture, a compound, and a molded article.

The gelation time of the curing accelerator-containing resin mixture andthe physical properties (the Shore hardness, the glass transitiontemperature, the flexural properties, and the moisture absorption justafter the molding) of the molded article were measured. The results areshown in Table 6.

Example 38

Example 31 was repeated except that the highly reactive low-viscositymodified phenolic resin obtained in Example 24 was used together withthe highly reactive low-viscosity modified phenolic resin obtained inExample 4 which were mixed with each other in a ratio given in Table 6,and that the modified phenolic resin mixture and the epoxy resin wereblended in the ratio shown in Table 6 to obtain a curingaccelerator-containing resin mixture, a compound, and a molded article.

The gelation time of the curing accelerator-containing resin mixture andthe physical properties (the Shore hardness, the glass transitiontemperature, the flexural properties, and the moisture absorption justafter the molding) of the molded article were measured. The results areshown in Table 6.

Example 39

11.76 parts by weight of highly reactive low-viscosity modified phenolicresin obtained in Example 24 and 12.54 parts by weight of o-cresolnovolak epoxy resin (trade name; EOCN1020, produced by Nippon KayakuKabushiki Kaisha) were mixed and agitated by using an automatic mortarat a room temperature. Then, 0.25 parts by weight of triphenylphosphine(TPP) was added to the mixture as a curing accelerator to obtain acuring accelerator-containing resin mixture.

The gelation time of the curing accelerator-containing resin mixture wasmeasured and is shown in Table 7.

0.25 parts by weight of carnauba wax was added to and mixed with theresultant curing accelerator-containing resin mixture. Then, 0.20 partsby weight of carbon black and 75 parts by weight of fused silica (tradename; CRS1102-GT200T, produced by Tatsumori Co., Ltd.) as inorganicfillers were added to and mixed with the mixture. The resultant mixturewas mixed for additional 3-10 minutes by using rolls heated at 80-90° C.and was then cooled to a room temperature. The resultant mixture wasthen pulverized to obtain a compound. The formulation of this compoundis shown in Table 7.

The resultant compound was subjected to transfer molding conducted at175° C. for 90 seconds and was postcured at 175° C. for additional 6hours to obtain a molded article.

The Shore hardness, the glass transition temperature, the flexuralproperties, and the moisture absorption were measured on the resultantmolded article just after the molding. The results are shown in Table 7.

Examples 40-45

Example 39 was repeated except that the highly reactive low-viscositymodified phenolic resin obtained in Example 24 was replaced with thehighly reactive low-viscosity modified phenolic resins obtained in eachof Examples 25-30, and that the modified phenolic resin and the epoxyresin were blended in the ratio shown in Table 7 to obtain a curingaccelerator-containing resin mixture, a compound, and a molded article.

The gelation time of the curing accelerator-containing resin mixture andthe physical properties (the Shore hardness, the glass transitiontemperature, the flexural properties, and the moisture absorption justafter the molding) of the molded article were measured. The results areshown in Table 7.

                  TABLE 2-1    ______________________________________                 Exam-  Exam-   Exam-    Exam-                 ple 1  ple 2   ple 3    ple 4    ______________________________________    Amount of Powdery               (g)     100      100   100    100    modified phenolic    resin    Amount of Vanish               (g)     --       --    --     --    modified phenolic    resin    Amount of Phenol               (g)     200      150   200    200    Amount of o-cresol               (g)     --       --    --     --    Amount of m-cresol               (g)     --       --    --     --    Amount of Acid               (g)     5        5     5      5    catalyst (PTS)    Reaction   (° C.)                       120      140   140    160    temperature    Reaction time               (min.)  120      120   120    120    Solvent for               --      toluene/ toluene/                                      toluene/                                             toluene/    dilution           MIBK     MIBK  MIBK   MIBK    Amount of Reaction               (g)     182      195   195    197    product    Viscosity at 150° C.               (p)     3.0      2.0   1.2    0.6    (ICI viscomener)    Number average               --      490      470   400    430    molecular weight    (GPC)    OH equivalent               --      124      120   120    123    ______________________________________

                  TABLE 2-2    ______________________________________                 Exam-  Exam-   Exam-    Exam-                 ple 5  ple 6   ple 7    ple 8    ______________________________________    Amount of Powdery               (g)     100      100   100    100    modified phenolic    resin    Amount of Vanish               (g)     --       --    --     --    modified phenolic    resin    Amount of Phenol               (g)     200      200   --     --    Amount of o-cresol               (g)     --       --    200    200    Amount of m-cresol               (g)     --       --    --     --    Amount of Acid               (g)     5        5     5      5    catalyst (PTS)    Reaction   (° C.)                       180      200   140    160    temperature    Reaction time               (min.)  120      120   120    120    Solvent for               --      toluene/ toluene/                                      toluene/                                             toluene/    dilution           MIBK     MIBK  MIBK   MIBK    Amount of Reaction               (g)     205      196   192    195    product    Viscosity at 150° C.               (p)     0.5      0.2   1.7    1.0    (ICI viscomener)    Number average               --      350      330   452    420    molecular weight    (GPC)    OH equivalent               --      120      126   135    140    ______________________________________

                  TABLE 2-3    ______________________________________                                   Comparative                  Example 9                         Example 10                                   Example 1    ______________________________________    Amount of Powdery               (g)      100      --      100    modified phenolic    resin    Amount of Vanish               (g)      --       200     --    modified phenolic    resin    Amount of Phenol               (g)      --       200     200    Amount of o-cresol               (g)      --       --      --    Amount of m-cresol               (g)      200      --      --    Amount of Acid               (g)      5        5       5    catalyst   (PTS)    Reaction   (° C.)                        140      160     95    temperature    Reaction time               (min.)   120      120     120    Solvent for               --       toluene/ toluene/                                         toluene/    dilution            MIBK     MIBK    MIBK    Amount of Reaction               (g)      185      200     175    product    Viscosity at 150° C.               (p)      3.0      0.8     5.5    (ICI viscomener)    Number average               --       448      370     550    molecular weight    (GPC)    OH equivalent               --       134      120     127    ______________________________________

                  TABLE 3-1    ______________________________________                       Exam- Exam-   Exam-                       ple 11                             ple 12  ple 13    ______________________________________    Modified           Example 3    parts by 9.17    phenolic            weight    resin  Example 4    parts by       9.31                        weight           Example 5    parts by             9.17                        weight           Example 7    parts by                        weight           Example 8    parts by                        weight           Example 9    parts by                        weight           Example 10   parts by                        weight           Comparative  parts by           Example 1    weight    Epoxy  YX-4000H     parts by 14.89 14.75 14.89    resin               weight    Curing TPP          parts by 0.49  0.49  0.49    accelerator         weight    Fused  CRS1102-GT200T                        parts by 75    75    75    silica              weight    Camauba wax     parts by 0.25    0.25  0.25                    weight    Carbon black    parts by 0.20    0.20  0.20                    weight    Gelation time   (170° C./                             46      46    52                    sec)    Shore hardness just after                    --       75      75    70    molding    Glass transition temperature (Tg)                    (° C.)                             128     124   125    Flexural           room         (kgf/mm.sup.2)                                 17    10    15    strength           temperature    Flexural           room         (kgf/mm.sup.2)                                 1890  1920  1920    modulus           temperature    Moisture           85° C./85%-72 hr                        (wt. %)  0.210 0.207 0.203    absorption           85° C./85%-168 hr                        (wt. %)  0.300 0.293 0.289    ______________________________________

                  TABLE 3-2    ______________________________________                       Exam- Exam-   Exam-                       ple 14                             ple 15  ple 16    ______________________________________    Modified           Example 3    parts by    phenolic            weight    resin  Example 4    parts by                        weight           Example 5    parts by                        weight           Example 7    parts by 9.84                        weight           Example 8    parts by       10.05                        weight           Example 9    parts by             9.80                        weight           Example 10   parts by                        weight           Comparative  parts by           Example 1    weight    Epoxy  YX-4000H     parts by 14.22 14.01 14.26    resin               weight    Curing TPP          parts by 0.49  0.49  0.49    accelerator         weight    Fused  CRS1102-GT200T                        parts by 75    75    75    silica              weight    Camauba wax     parts by 0.25    0.25  0.25                    weight    Carbon black    parts by 0.20    0.20  0.20                    weight    Gelation time   (170° C./                             53      55    46                    sec)    Shore hardness just after                    --       64      70    67    molding    Glass transition temperature (Tg)                    (° C.)                             122     120   132    Flexural           room         (kgf/mm.sup.2)                                 12    16    12    strength           temperature    Flexural           room         (kgf/mm.sup.2)                                 1840  1950  1920    modulus           temperature    Moisture           85° C./85%-72 hr                        (wt. %)  0.193 0.185 0.194    absorption           85° C./85%-168 hr                        (wt. %)  0.286 0.270 0.285    ______________________________________

                  TABLE 3-3    ______________________________________                               Comparative                       Example 17                               Example 2    ______________________________________    Modified           Example 3    parts by    phenolic            weight    resin  Example 4    parts by                        weight           Example 5    parts by                        weight           Example 7    parts by                        weight           Example 8    parts by                        weight           Example 9    parts by                        weight           Example 10   parts by 9.17                        weight           Comparative  parts by         9.48           Example 1    weight    Epoxy  YX-4000H     parts by 14.89   14.58    resin               weight    Curing TPP          parts by 0.49    0.49    accelerator         weight    Fused  CRS1102-GT200T                        parts by 75      75    silica              weight    Camauba wax     parts by 0.25      0.25                    weight    Carbon black    parts by 0.20      0.20                    weight    Gelation time   (170° C./                             46        60                    sec)    Shore hardness just after                    --       75        77    molding    Glass transition temperature (Tg)                    (° C.)                             120       140    Flexural           room         (kgf/mm.sup.2)                                 16      15    strength           temperature    Flexural           room         (kgf/mm.sup.2)                                 1950    1800    modulus           temperature    Moisture           85° C./85%-72 hr                        (wt. %)  0.200   0.220    absorption           85° C./85%-168 hr                        (wt. %)  0.290   0.316    ______________________________________

                  TABLE 4-1    ______________________________________                       Exam- Exam-   Exam-                       ple 18                             ple 19  ple 20    ______________________________________    Modified           Example 1    parts by 9.39    phenolic            weight    resin  Example 2    parts by       9.19                        weight           Example 3    parts by             9.19                        weight           Example 6    parts by                        weight           Example 8    parts by                        weight           Example 10   parts by                        weight           Comparative  parts by           Example 1    weight    Epoxy  EOCN1020     parts by 14.91 15.11 15.11    resin               weight    Curing TPP          parts by 0.25  0.25  0.25    accelerator         weight    Fused  CRS1102-GT200T                        parts by 75    75    75    silica              weight    Camauba wax     parts by 0.25    0.25  0.25                    weight    Carbon black    parts by 0.20    0.20  0.20                    weight    Gelation time   (170° C./                             44      50    55                    sec)    Shore hardness just after                    --       85      85    85    molding    Glass transition temperature (Tg)                    (° C.)                             169     167   160    Flexural           room         (kgf/mm.sup.2)                                 17    19    18    strength           temperature    Flexural           room         (kgf/mm.sup.2)                                 1880  1900  1900    modulus           temperature    Moisture           85° C./85%-72 hr                        (wt. %)  0.217 0.207 0.200    absorption           85° C./85%-168 hr                        (wt. %)  0.315 0.306 0.300    ______________________________________

                  TABLE 4-2    ______________________________________                       Example 21                               Example 22    ______________________________________    Modified           Example 1    parts by    phenolic            weight    resin  Example 2    parts by                        weight           Example 3    parts by                        weight           Example 6    parts by 9.48                        weight           Example 8    parts by         10.10                        weight           Example 10   parts by                        weight           Comparative  parts by           Example 1    weight    Epoxy  EOCN1020     parts by 14.82   14.20    resin               weight    Curing TPP          parts by 0.25    0.25    accelerator         weight    Fused  CRS1102-GT200T                        parts by 75      75    silica              weight    Camauba wax     parts by 0.25      0.25                    weight    Carbon black    parts by 0.20      0.20                    weight    Gelation time   (170° C./                             56        65                    sec)    Shore hardness just after                    --       85        83    molding    Glass transition temperature (Tg)                    (° C.)                             160       145    Flexural           room         (kgf/mm.sup.2)                                 18      19    strength           temperature    Flexural           room         (kgf/mm.sup.2)                                 1890    1900    modulus           temperature    Moisture           85° C./85%-72 hr                        (wt. %)  0.192   0.175    absorption           85° C./85%-168 hr                        (wt. %)  0.289   0.258    ______________________________________

                  TABLE 4-3    ______________________________________                               Comparative                       Example 23                               Example 3    ______________________________________    Modified           Example 1    parts by    phenolic            weight    resin  Example 2    parts by                        weight           Example 3    parts by                        weight           Example 6    parts by                        weight           Example 8    parts by                        weight           Example 10   parts by 9.19                        weight           Comparative  parts by         9.53           Example 1    weight    Epoxy  EOCN1020     parts by 15.11   14.77    resin               weight    Curing TPP          parts by 0.25    0.25    accelerator         weight    Fused  CRS1102-GT200T                        parts by 75      75    silica              weight    Camauba wax     parts by 0.25      0.25                    weight    Carbon black    parts by 0.20      0.20                    weight    Gelation time   (170° C./                             57        40                    sec)    Shore hardness just after                    --       85        85    molding    Glass transition temperature (Tg)                    (° C.)                             158       169    Flexural           room         (kgf/mm.sup.2)                                 18      18    strength           temperature    Flexural           room         (kgf/mm.sup.2)                                 1900    1800    modulus           temperature    Moisture           85° C./85%-72 hr                        (wt. %)  0.198   0.235    absorption           85° C./85%-168 hr                        (wt. %)  0.296   0.344    ______________________________________

                  TABLE 5-1    ______________________________________                 Exam-  Exam-   Exam-    Exam-                 ple 24 ple 25  ple 26   ple 27    ______________________________________    Amount of Powdery               (g)     100      100   100    100    modified phenolic    resin    Amount of Vanish               (g)     --       --    --     --    modified phenolic    resin    Amount of α-               (g)     250      250   250    250    naphthol    Amount of β-               (g)     --       --    --     --    naphthol    Amount of Phenol               (g)     --       --    --     --    Amount of Acid               (g)     5        5     5      5    catalyst    Reaction   (° C.)                       120      140   160    180    temperature    Reaction time               (min.)  120      120   120    120    Solvent for               --      MIBK     MIBK  MIBK   MIBK    dilution    Amount of Reaction               (g)     230      243   250    258    product    Viscosity at 150° C.               (p)     4.4      4     2      1.2    (ICI viscomener)    Number average               --      535      486   428    370    molecular weight    (GPC)    OH equivalent               --      185      180   178    176    ______________________________________

                  TABLE 5-2    ______________________________________                 Example 28                         Example 29                                   Example 30    ______________________________________    Amount of Powdery               (g)     100       100     --    modified phenoiic    resin    Amount of Vanish               (g)     --        --      200    modified phenolic    resin    Amount of α-               (g)     101       --      250    naphtho    Amount of β-               (g)     --        200     --    naphthol    Amount of Phenol               (g)     132       --      --    Amount of Acid               (g)     5         5       5    catalyst    Reaction   (° C.)                       160       140     120    temperature    Reaction time               (min.)  60        60      120    Solvent for               --      toluene/  MIBK    MIBK    dilution           MIBK    Amount of Reaction               (g)     220       220     230    product    Viscosity at 150° C.               (p)     4.1       4.3     4.4    (ICI viscomener)    Number average               --      563       560     523    molecular weight    (GPC)    OH equivalent               --      149       185     185    ______________________________________

                  TABLE 6-1    ______________________________________                       Exam- Exam-   Exam-                       ple 31                             ple 32  ple 33    ______________________________________    Modified           Example 4    parts by    phenolic            weight    resin  Example 24   parts by 11.71                        weight           Example 25   parts by       11.54                        weight           Example 26   parts by             11.49                        weight           Example 27   parts by                        weight           Example 28   parts by                        weight           Example 29   parts by                        weight           Example 30   parts by                        weight    Epoxy  YX-4000H     parts by 12.35 12.52 12.57    resin               weight    Curing TPP          parts by 0.49  0.49  0.49    accelerator         weight    Fused  CRS1102-GT200T                        parts by 75    75    75    silica              weight    Carnuba wax     parts by 0.25    0.25  0.25                    weight    Carbon black    parts by 0.20    0.20  0.20                    weight    Gelation time   (170° C./                             45      47    50                    sec)    Shore hardness just after                    --       73      73    73    molding    Glass transition temperature (Tg)                    (° C.)                             162     160   158    Flexural           room         (kgf/mm.sup.2)                                 16    15    15    strength           temperature    Flexural           room         (kgf/mm.sup.2)                                 1870  1820  1830    modulus           temperature    Moisture           85° C./85%-72 hr                        (wt. %)  0.159 0.154 0.149    absorption           85° C./85%-168 hr                        (wt. %)  0.230 0.220 0.212    ______________________________________

                  TABLE 6-2    ______________________________________                       Exam- Exam-   Exam-                       ple 34                             ple 35  ple 36    ______________________________________    Modified           Example 4    parts by    phenolic            weight    resin  Example 24   parts by                        weight           Example 25   parts by                        weight           Example 26   parts by                        weight           Example 27   parts by 11.42                        weight           Example 28   parts by       10.41                        weight           Example 29   parts by             11.71                        weight           Example 30   parts by                        weight    Epoxy  YX-4000H     parts by 12.64 13.65 12.35    resin               weight    Curing TPP          parts by 0.49  0.49  0.49    accelerator         weight    Fused  CRS1102-GT200T                        parts by 75    75    75    silica              weight    Camauba wax     parts by 0.25    0.25  0.25                    weight    Carbon black    parts by 0.20    0.20  0.20                    weight    Gelation time   (170° C./                             54      53    58                    sec)    Shore hardness just after                    --       71      67    67    molding    Glass transition temperature (Tg)                    (° C.)                             158     144   152    Flexural           room         (kgf/mm.sup.2)                                 16    16    13    strength           temperature    Flexural           room         (kgf/mm.sup.2)                                 1850  1800  1770    modulus           temperature    Moisture           85° C./85%-72 hr                        (wt. %)  0.135 0.190 0.148    absorption           85° C./85%-168 hr                        (wt. %)  0.198 0.273 0.219    ______________________________________

                  TABLE 6-3    ______________________________________                       Example 37                               Example 38    ______________________________________    Modified           Example 4    parts by         5.18    phenolic            weight    resin  Example 24   parts by         5.18                        weight           Example 25   parts by                        weight           Example 26   parts by                        weight           Example 27   parts by                        weight           Example 28   parts by                        weight           Example 29   parts by                        weight           Example 30   parts by 11.71                        weight    Epoxy  YX-4000H     parts by 12.35   13.71    resin               weight    Curing TPP          parts by 0.49    0.49    accelerator         weight    Fused  CRS1102-GT200T                        parts by 75      75    silica              weight    Camauba wax     parts by 0.25      0.25                    weight    Carbon black    parts by 0.20      0.20                    weight    Gelation time   (170° C./                             45        47                    sec)    Shore hardness just after                    --       73        70    molding    Glass transition temperature (Tg)                    (° C.)                             161       140    Flexural           room         (kgf/mm.sup.2)                                 16      14    strength           temperature    Flexural           room         (kgf/mm.sup.2)                                 1860    1850    modulus           temperature    Moisture           85° C./85%-72 hr                        (wt. %)  0.158   0.183    absorption           85° C./85%-168 hr                        (wt. %)  0.229   0.260    ______________________________________

                  TABLE 7-1    ______________________________________                       Exam- Exam-   Exam-                       ple 39                             ple 40  ple 41    ______________________________________    Modified           Example 24   parts by 11.76    phenolic            weight           Example 25   parts by       11.59                        weight           Example 26   parts by             11.54                        weight           Example 27   parts by                        weight           Example 28   parts by                        weight           Example 29   parts by                        weight           Example 30   parts by                        weight    Epoxy  EOCN1020     parts by 12.54 12.71 12.76    resin               weight    Curing TPP          parts by 0.25  0.25  0.25    accelerator         weight    Fused  CRS1102-GT200T                        parts by 75    75    75    silica              weight    Camauba wax     parts by 0.25    0.25  0.25                    weight    Carbon black    parts by 0.20    0.20  0.20                    weight    Gelation time   (170° C./                             42      44    48                    sec)    Shore hardness just after                    --       84      83    82    molding    Glass transition temperature (Tg)                    (° C.)                             189     187   185    Flexural           room         (kgf/mm.sup.2)                                 18    17    17    strength           temperature    Flexural           room         (kgf/mm.sup.2)                                 1900  1890  1800    modulus           temperature    Moisture           85° C./85%-72 hr                        (wt. %)  0.164 0.152 0.146    absorption           85° C./85%-168 hr                        (wt. %)  0.237 0.224 0.220    ______________________________________

                  TABLE 7-2    ______________________________________                       Example 42                               Example 43    ______________________________________    Modified           Example 24   parts by    phenolic            weight           Example 25   parts by                        weight           Example 26   parts by                        weight           Example 27   parts by 11.47                        weight           Example 28   parts by         10.47                        weight           Example 29   parts by                        weight           Example 30   parts by                        weight    Epoxy  EOCN1020     parts by 12.83   13.83    resin               weight    Curing TPP          parts by 0.25    0.25    accelerator         weight    Fused  CRS1102-GT200T                        parts by 75      75    silica              weight    Camauba wax     parts by 0.25      0.25                    weight    Carbon black    parts by 0.20      0.20                    weight    Gelation time   (170° C./                             49        48                    sec)    Shore hardness just after                    --       80        77    molding    Glass transition temperature (Tg)                    (° C.)                             184       175    Flexural           room         (kgf/mm.sup.2)                                 16      18    strength           temperature    Flexural           room         (kgf/mm.sup.2)                                 1790    1800    modulus           temperature    Moisture           85° C./85%-72 hr                        (wt. %)  0.128   0.203    absorption           85° C./85%-168 hr                        (wt. %)  0.189   0.297    ______________________________________

                  TABLE 7-3    ______________________________________                       Example 44                               Example 45    ______________________________________    Modified           Example 24   parts by    phenolic            weight           Example 25   parts by                        weight           Example 26   parts by                        weight           Example 27   parts by                        weight           Example 28   parts by                        weight           Example 29   parts by 11.76                        weight           Example 30   parts by         11.76                        weight    Epoxy  EOCN1020     parts by 12.54   12.54    resin               weight    Curing TPP          parts by 0.25    0.25    accelerator         weight    Fused  CRS1102-GT200T                        parts by 75      75    silica              weight    Camauba wax     parts by 0.25      0.25                    weight    Carbon black    parts by 0.20      0.20                    weight    Gelation time   (170° C./                             54        42                    sec)    Shore hardness just after                    --       74        85    molding    Glass transition temperature (Tg)                    (° C.)                             178       188    Flexural           room         (kgf/mm.sup.2)                                 14      18    strength           temperature    Flexural           room         (kgf/mm.sup.2)                                 1760    1890    modulus           temperature    Moisture           85° C./85%-72 hr                        (wt. %)  0.151   0.165    absorption           85° C./85%-168 hr                        (wt. %)  0.218   0.236    ______________________________________

We claim:
 1. A molding material based on a modified phenolic resincomprising:(A) a low-melt-viscosity modified phenolic resin having aresin melt viscosity at 150° C. of from 0.2 to 4.5 poises obtained bypolycondensating a petroleum heavy oil or pitch, a formaldehyde polymer,and a phenol in the presence of an acid catalyst to prepare a modifiedphenolic resin; and reacting the resultant modified phenolic resin witha phenol at a temperature of from 140° C. and not more than 200° C. inthe presence of the acid catalyst to lower the molecular weight of themodified phenolic resin; and (B) an epoxy resin.
 2. A molding materialbased on the modified phenolic resin as claimed in claim 1 wherein thehighly reactive low-viscosity modified phenolic resin has the resin meltviscosity at 150° C. of from 0.2 to 3.0 poises.
 3. A molding materialbased on the modified phenolic resin as claimed in claim 1 wherein thehighly reactive low-viscosity modified phenolic resin has the resin meltviscosity at 150° C. of from 1.0 to 4.5 poises.
 4. A molding materialbased on the modified phenolic resin as claimed in claim 1 furthercomprising (C) a curing agent and/or a curing accelerator, and (D) aninorganic filler.
 5. A molding material based on the modified phenolicresin as claimed in claim 1 wherein the highly reactive low-viscositymodified phenolic resin (A) is mixed with the epoxy resin (B) in a ratioof 10:90 to 90:10 parts by weight.
 6. A material for electrical andelectronic parts which is produced by molding the molding material basedon the modified phenolic resin as claimed in claim
 1. 7. A semiconductorsealer which is made from the molding material based on the modifiedphenolic resin as claimed in claim 1.